The reaction utilizing the carbon radical formed from an organohalogen compound is important in organic synthesis as a means for constructing a cyclic skeleton by way of carbon--carbon linkage but, in many instances, the radical on the carbon skeleton is reduced by a hydrogen donor, which eliminates the functional group.
On the other hand, the inventors reported previously that an alcohol can be provided by capturing the alkyl radical intermediate formed from an alkyl halide in the presence of Bu.sub.3 SnH and AIBN (2,2'-azobisisobutyronitrile) with molecular oxygen. This technology is instrumental in organic synthesis as a means for directly substituting a hydroxyl group for a halogen atom on a carbon skeleton. Meanwhile, Prandi and coworkers obtained a similar result by reacting a substrate halide with 0.05.about.0.1 equivalent of Bu.sub.3 SnCl, 1 equivalent of the radical reaction promoter AIBN and 6 equivalents of NaBH.sub.4 in hot ethanol under bubbling with air (Tetrahedron Letters, vol. 37, pages 3117-3120, 1996).
However, those methods also have aspects to be improved for application to large-scale reactions in that the halide which can be a substrate is limited to highly reactive compounds such as alkyl iodides, allyl bromide and benzyl bromide and that the reaction requires either 2 equivalents of an organotin compound or 0.05.about.0.1 equivalent of an organotin compound plus 1 equivalent of the unstable AIBN and, in addition, requires a large excess of oxygen as well.